Amnesia for Complex Naturalistic Scenes and for Objects Following Fornix Transection in the Rhesus Monkey

Abstract

Rhesus monkeys (Macaca mulatta) were trained to discriminate among many complex naturalistic scenes. The scenes were still frames from a cinema film. They were presented as the discriminative stimuli in a concurrent discrimination learning task in which each discriminative stimulus was presented on one trial each day. Learning of this task was severely impaired by fornix transection. The same animals were also deficient in a similar concurrent discrimination learning task, with each discriminative stimulus presented on one trial each day, but with objects, not complex scenes, as the stimulus material. The impairment in object discrimination learning in the present experiment is attributable to an interaction of object discrimination learning with scene discrimination learning, and can be understood as an effect of interference in long-term memory. In contrast to these impairments in long-term memory, a test of within-session learning of complex scenes, in which the average interval between successive presentations of the same stimulus was < 3 min, was performed without significant impairment by the fornix-transected animals. These results show that long-term memory for complex naturalistic scenes reveals analogues in the monkey of human episodic memory and its impairment in amnesia.

Neural dynamics of autistic behaviors: Cognitive, emotional, and timing substrates.

“…The lack of timed control over variable delays can thus harm behavior more when it is necessary to shift attention among different sets of cues. Gaffan (1992) has described analogous data from hippocampectomized monkeys.…”

H. M.’s Medial Temporal Lobe Lesion: Findings from Magnetic Resonance Imaging

“…By one view, each of these regions performs qualitatively similar functions, and the progressive severity of amnesia that is observed with increased damage is attributable to loss of the capacity to perform the primary function of this region (Zola-Morgan et al, 1994). An alternative view is that each of these brain regions contributes differentially to memory function (Murray, 1992;Gaffan, 1992aGaffan, ,b,c, 1994Eacott et al, 1994;Eichenbaum et al, 1994;Meunier et al, 1996), perhaps by using different cognitive strategies, and the progressive amnesia is attributable to the elimination of alternate means for forming memories. Because pathology rarely invades a singular, neuroanatomical region in the medial temporal lobe, the ultimate resolution of this issue may rely on other methods such as functional brain imaging.…”

“…Clearly, each of the multiple areas within the medial temporal lobe region, including the hippocampal formation and the perirhinal cortex, contributes to normal memory function. It is unclear, however, whether each of these regions is performing essentially similar mnemonic tasks so that the deficit becomes more severe when more of these processing regions are removed (Zola-Morgan et al, 1994), or whether there are dissociations of function within the medial temporal lobe region (Gaffan, 1992a(Gaffan, ,b,c, 1994Murray, 1992;Eacott et al, 1994;Eichenbaum et al, 1994;Meunier et al, 1996) so that the memory impairment becomes more severe as more strategies for task-solution are eliminated. It will be essential to conduct parallel studies in monkeys and human amnesic subjects to determine the precise cognitive function of each of these medial temporal lobe regions.…”

Does the cingulate cortex contribute to spatial conditional associative learning in the rat?

“…For example, both the anterior and retrosplenial cingulate regions are connected with the hippocampus and the anterior thalamic nuclei (see below), two brain structures known to play a role in spatial learning and memory (e.g., Olton and Papas, 1979;Morris et al, 1982;Aggleton et al, 1996;Warburton and Aggleton, 1999). The retrosplenial and the anterior cingulate cortex (ACC) are bi-directionally connected with the anterior thalamic nuclei Finch et al, 1984;Seki and Zyo, 1984;Shibata, 1998; Van Groen and Wyss, 1990a, 1992Shibata and Naito, 2005). The retrosplenial cortex is also connected with the hippocampal formation, mostly the posterior subiculum (Finch et al, 1984;Seki and Zyo, 1984;Van Groen and Wyss, 1990a, 1992.…”

“…The retrosplenial and the anterior cingulate cortex (ACC) are bi-directionally connected with the anterior thalamic nuclei Finch et al, 1984;Seki and Zyo, 1984;Shibata, 1998; Van Groen and Wyss, 1990a, 1992Shibata and Naito, 2005). The retrosplenial cortex is also connected with the hippocampal formation, mostly the posterior subiculum (Finch et al, 1984;Seki and Zyo, 1984;Van Groen and Wyss, 1990a, 1992. To a lesser extent, the ACC has bi-directional connections with the hippocampal formation, both directly and indirectly, through the retrosplenial cortex (Vogt and Miller, 1983;Finch et al, 1984;Van Groen and Wyss, 1990b).…”